The present invention relates to a wiper blade and more particularly to an anti-windlift wiper blade superstructure.
Windshield wiper blade superstructures are commonly of U-shaped cross section. They are subject to forces tending to lift the blade assembly off of the windshield by the car-created windstream at high speeds, thus rendering them ineffective for adequate wiping under such conditions. Superstructures in which the levers have a round cross section to overcome this problem are known in the prior art. Examples of these are the wiper blades disclosed in British Patent 858,220 published Jan. 11, 1961 and British Pat. No. 1,109,971 published April 18, 1968. A similar construction appears in U.S. Design Patent 221,535 issued Aug. 24, 1971. There appears to be a single bowed wire superstructure in U.S. Pat. No. 3,132,367 issued May 12, 1964 which is substantially different in mode of operation. All of these patents disclose a solid wire construction rather than a tubular construction and, therefore, introduce certain inherent functional and manufacturing difficulties.
Wiper blades of solid wire having a multiple lever system require separate parts for securing the wiping element to the superstructure and for the connections between the levers. This introduces additional assembly steps thereby increasing labor time and the possibility of lack of stability at the joints. The solid wire construction also results in substantially increased weight relative to its strength in resistance to bending and torsion forces. Design Patent No. 221,535 utilizes U-shaped secondary levers at its outboard ends which severely diminishes the anti-windlift effect.